This invention relates to filters, in general, and to components having filters and their methods of manufacture and operation, in particular.
Physical sensor components such as, for example, pressure sensors can be used in automotive, industrial, consumer, and various other applications. Elastic gels, polymers, diaphragms, membranes, and other coatings or encapsulants have been used to protect the pressure sensors from the potentially corrosive environments in which the pressure sensors operate. However, none of these encapsulants are entirely impermeable to the corrosive environments. Furthermore, the encapsulants do not completely satisfy many stringent reliability requirements demanded by customers who use the pressure sensors.
A common failure mechanism for a silicon pressure sensor having a prior art coating or encapsulant occurs due to diffusion of the corrosive media through the encapsulant, which delaminates the encapsulant from the silicon pressure sensor. This delamination exposes portions of the silicon pressure sensor that subsequently corrode from the direct exposure to the corrosive media.
In addition to this common failure mechanism, most of the prior art coatings and encapsulants adversely affect the performance of the silicon pressure sensor. These adverse effects can include a pressure offset due to acceleration and/or a gel over-expansion due to a rapid change in pressure. Both of these adverse effects can severely limit the use of the silicon pressure sensor.
Accordingly, a need exists for an improved component that provides effective corrosion protection while not adversely affecting the performance of the component.